Due to superior cleaning power and good handlability, synthetic detergents in the laundering of clothing have gained overwhelming support. However, not all of the gains to consumers from synthetic detergents are positive. For example, while synthetic detergents have gone through many improvement processes in response to the issue of environmental burden caused by alkylbenzene sulfonic acid soda and phosphate builders blended therein, issues have recently begun to be raised regarding adverse affects on organisms from synthetic detergents including the possibility of being an endocrine disrupting chemical. Also, the fact cannot be escaped that a substantial amount of surface-active agents included in synthetic detergents remains on clothing despite careful rinsing, nor may the probability be denied that such a surface-active agent passes through the skin to bring about any number of affects on the human body. Furthermore, the large quantity of water that is drained away over the course of the plurality of rinses in order to remove the surface-active agent is a precious resource that should not be wasted.
Soaps that have been in use for a long time and considered safe cannot be a substitution even for those who question safeness of synthetic detergents due to the inferior handlability thereof. In addition, if a large amount must be used, even soaps having better biodegradability compared to synthetic detergents do not seem to necessarily lead to a reduction in impact on the environment.
Although excellent detergency through surface-active agents is widely known, when considering the effects on living beings and the environment, appearance of a new detergent having no added surface-active agent or including a drastically reduced amount of surface-active agent, yet having the same cleaning power and handlability as synthetic detergents has been awaited.
Laundry detergent having substantially no added surface-active agent and having alkaline inorganic salt is a main ingredient is in use, as well as the washing soda (sodium carbonate hydrate) of old. More recently, as disclosed in Japanese Patent Application Laid-open No. Hei 9-87678, a detergent is proposed having added sodium bicarbonate (baking soda) and further including an enzyme with the aim of strengthening cleaning power.
Nevertheless, these conventionally used laundry detergents having no alkaline inorganic salt added as a main ingredient are inferior in detergency and handlability compared with laundry soaps and synthetic detergents, and in particular lag behind synthetic detergents.
An object of the present invention is to provide a detergent composition and washing method using the same, wherein the detergent composition includes substantially no surface-active agents, which have been questioned in terms of safeness on the human body and reduction in environmental impact, or having an amount of surface-active agent that is drastically reduced while having detergency and handlability that is equivalent or superior to that of conventional laundry soaps and synthetic detergents having a surface-active agent as a main ingredient.